/**
* @license Copyright (c) 2003-2026, CKSource Holding sp. z o.o. All rights reserved.
* For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
*/
/**
* @module engine/model/history
*/
import { type Operation } from "./operation/operation.js";
/**
* `History` keeps the track of all the operations applied to the {@link module:engine/model/document~ModelDocument document}.
*/
export declare class History {
	/**
	* Operations added to the history.
	*/
	private _operations;
	/**
	* Holds an information which {@link module:engine/model/operation/operation~Operation operation} undoes which
	* {@link module:engine/model/operation/operation~Operation operation}.
	*
	* Keys of the map are "undoing operations", that is operations that undone some other operations. For each key, the
	* value is an operation that has been undone by the "undoing operation".
	*/
	private _undoPairs;
	/**
	* Holds all undone operations.
	*/
	private _undoneOperations;
	/**
	* A map that allows retrieving the operations fast based on the given base version.
	*/
	private _baseVersionToOperationIndex;
	/**
	* The history version.
	*/
	private _version;
	/**
	* The gap pairs kept in the <from,to> format.
	*
	* Anytime the `history.version` is set to a version larger than `history.version + 1`,
	* a new <lastHistoryVersion, newHistoryVersion> entry is added to the map.
	*/
	private _gaps;
	/**
	* The version of the last operation in the history.
	*
	* The history version is incremented automatically when a new operation is added to the history.
	* Setting the version manually should be done only in rare circumstances when a gap is planned
	* between history versions. When doing so, a gap will be created and the history will accept adding
	* an operation with base version equal to the new history version.
	*/
	get version(): number;
	set version(version: number);
	/**
	* The last history operation.
	*/
	get lastOperation(): Operation | undefined;
	/**
	* Adds an operation to the history and increments the history version.
	*
	* The operation's base version should be equal to the history version. Otherwise an error is thrown.
	*/
	addOperation(operation: Operation): void;
	/**
	* Returns operations from the given range of operation base versions that were added to the history.
	*
	* Note that there may be gaps in operations base versions.
	*
	* @param fromBaseVersion Base version from which operations should be returned (inclusive).
	* @param toBaseVersion Base version up to which operations should be returned (exclusive).
	* @returns History operations for the given range, in chronological order.
	*/
	getOperations(fromBaseVersion?: number, toBaseVersion?: number): Array<Operation>;
	/**
	* Returns operation from the history that bases on given `baseVersion`.
	*
	* @param baseVersion Base version of the operation to get.
	* @returns Operation with given base version or `undefined` if there is no such operation in history.
	*/
	getOperation(baseVersion: number): Operation | undefined;
	/**
	* Marks in history that one operation is an operation that is undoing the other operation. By marking operation this way,
	* history is keeping more context information about operations, which helps in operational transformation.
	*
	* @param undoneOperation Operation which is undone by `undoingOperation`.
	* @param undoingOperation Operation which undoes `undoneOperation`.
	*/
	setOperationAsUndone(undoneOperation: Operation, undoingOperation: Operation): void;
	/**
	* Checks whether given `operation` is undoing any other operation.
	*
	* @param operation Operation to check.
	* @returns `true` if given `operation` is undoing any other operation, `false` otherwise.
	*/
	isUndoingOperation(operation: Operation): boolean;
	/**
	* Checks whether given `operation` has been undone by any other operation.
	*
	* @param operation Operation to check.
	* @returns `true` if given `operation` has been undone any other operation, `false` otherwise.
	*/
	isUndoneOperation(operation: Operation): boolean;
	/**
	* For given `undoingOperation`, returns the operation which has been undone by it.
	*
	* @returns Operation that has been undone by given `undoingOperation` or `undefined`
	* if given `undoingOperation` is not undoing any other operation.
	*/
	getUndoneOperation(undoingOperation: Operation): Operation | undefined;
	/**
	* Resets the history of operations.
	*/
	reset(): void;
}